Evolution of Influenza A Viruses (IAV) in Swine

Published: 09 Apr 2019 | Last Updated: 09 Apr 2019 10:35:31

Dr Nicola Lewis has been awarded a grant by the US Department of Agriculture (USDA) to work on Characterization of the Evolution of Influenza A Viruses (IAV) in Swine. This project will be run in partnership with the Animal and Plant Health Agency (APHA) to deliver this project as part of a global initiative in close collaboration with the Centers of Excellence for Influenza Research and Surveillance (CEIRS) network, and the United States Department of Agriculture (USDA).

The first pandemic of the 21st century was caused by a strain of influenza A virus (IAV) that was transmitted from pigs into humans, highlighting the importance of swine as reservoirs for pandemic viruses. Many strains of IAV that circulate in pigs are derived from repeated introductions of human IAV into swine populations. Once in pigs, IAV continues to evolve and diverge such that humans are no longer immune to them, presenting a continual potential pandemic threat. This project will investigate the relationship between the evolution of IAV in swine and the risk to human health.

In collaboration with the CEIRS network and USDA, we will quantify the relatedness of currently circulating swine and human IAV by antigenic cartography, a method that uses experimental assay data to algorithmically determine distances between the different viruses, allowing us to visualise them in Euclidean space. Such antigenic ‘maps’ help us identify particularly divergent swine strains, which may pose a threat, for further characterisation. We will combine this data with phylodynamic methods, which use IAV genome sequence data and associated epidemiological data to understand genetic diversity, spatial dynamics, inter-species transmission, and reassortment (where gene segments of IAV are swapped between different strains) in these viruses globally. Finally, we hope to identify swine IAV with limited human population immunity by quantifying the immune response from age-stratified human sera representing multiple geographic regions.

The results from these analyses should inform both public and animal health decisions for control of influenza and for pandemic preparedness.